Sonnet 145 stands out in the collection for several reasons. Some factual, some conjectural, some somewhere in-between.

Most obviously and beyond interpretation evident is the fact that it is the only poem composed in iambic tetrameter: it consists of 14 lines of eight syllables each, in contrast to the iambic pentameters present in all the other sonnets, giving each line of those ten or eleven syllables.

Also still difficult to dispute, though already in the realm of opinion, is the observation, so as not to say contention, put forward by many scholars and commentators, that the sonnet is poetically, stylistically, literarily 'slight': it strikes a simple tone, uses some extremely familiar imagery and analogy, and is, as far as we can tell, mostly devoid of the high level compositional and rhetorical devices used in many of the other, 'regular', sonnets.
Pure supposition, though intelligent and fully valid as a suggestion, is the idea that the sonnet puns on the name Hathaway and is therefore not about the Dark Lady or any other mistress, but about Shakespeare's wife, Anne; and even more adventurous is the conjecture drawn from it that therefore the poem be an early stab of Shakespeare's at as-yet-imperfect sonneteering: there is absolutely no proof that this is so, and it is just as conceivable that Shakespeare with Sonnet 145 deliberately and most intentionally not only employs a different format but also aims for a categorically different tone.